1. Technical Field
The present disclosure relates generally to the production of chlorobenzene by chlorination of benzene and, more particularly, to apparatus and methods for producing chlorobenzene via chlorination of benzene in a high shear process. The disclosure pertains still more particularly to the reduction of mass transfer limitations for converting benzene to chlorobenzene.
2. Background of the Invention
Chlorobenzene is used as a solvent with applications in certain pesticide formulations, automotive and industrial degreasers, and as a chemical intermediate to make herbicides, rubber and dyes. Benzene reacts with chlorine in the presence of a catalyst at room temperature, replacing one of the hydrogen atoms on the benzene ring with a chlorine atom. The catalyst is typically aluminum chloride or iron.
Iron is altered during the reaction such that chlorine forms iron (III) chloride, FeCl3.2Fe+3Cl2→2FeCl3.  (1)
This compound acts as the catalyst and behaves like aluminum chloride, AlCl3, in the reaction. The reaction between benzene and chlorine in the presence of either aluminum chloride or iron gives chlorobenzene, or, written more compactly:C6H6+Cl2→C6H5Cl+HCl.  (2)C6H5+Cl2→C6H4Cl+HCl.  (3)C6H4Cl+Cl2→C6H3Cl+HCl.  (4)As reaction (2) is the desired reaction, certain parameters must be maintained in the reactor. In certain cases, dichlorobenzene can be formed if reaction temperatures are not controlled properly.
There is a need in the industry for improved methods of producing chlorobenzene from benzene and chlorine whereby capital and/or operating costs are reduced via operation at lower temperature and/or pressure, product yield is increased and/or reaction time is decreased.